package com.briup.test;

import java.util.ArrayList;
public class A01_MapDemo1 {
    public static void main(String[] args) {

        ArrayList<String> a = new ArrayList();
        System.out.println(a.add("4"));
        a.add("4");
        a.add(1, "8");
        System.out.println(a);
        System.out.println(a.set(1, "9"));
        System.out.println(a);
        System.out.println(a.size());
    }

}


